This invention relates generally to functional electrical stimulation systems and more particularly to techniques to produce stimulation patterns for functional electrical stimulation systems usable for lower and/or upper extremities.
As is known in the art, research in upper and lower extremity functional electrical systems has been ongoing for a number of years. Functional electrical stimulation uses an electronic system to generate electrical pulses that are delivered to muscles of a patient who has muscle movement impairment. The muscle movement impairment is due to some condition that causes muscle paralysis. This condition can be nerve damage caused by accident or disease. The functional electrical stimulation system produces electrical signals that can be used by the patient to control muscle movement.
Practical electrical stimulation systems require a stimulation system that is small, lightweight and portable. Such a system would to allow a subject patient to operate the system to learn to perform everyday activities. On the other hand a practical system requires sufficient versatility and power to enable practical utilization of generated electrical stimulation patterns to produce a variety of muscle movements.
Several portable systems have been described in the literature. As is known, one of the problems common to these systems is the approach used to generate the electrical signal patterns. The described systems are either built for upper or lower extremity movement but not both or either. In general, the known systems cannot handle different types of sensors. Thus, systems are designed for a particular type of sensor associated with the desired type of stimulation. Further, the approaches used to process inputs to produce stimulation waveform generally are not sufficiently robust to accommodate different sensors.
Different sensors and algorithms are necessary for each type of stimulation because the characteristics of the upper and lower extremity movements are different. Lower extremity movements can be characterized as repetitive, predictable movements, whereas upper extremity movements are more spontaneous in character. A second problem is that for practical, useful movements of muscles generally several muscles must be operated in unison or concert to produce the practical movement. Thus, in addition to providing an algorithm which allows for relatively easy generation of such produced muscle movements, it is also desirable to provide an overall system that can be adapted for upper or lower extremity stimulation or both.